1. Field of the Invention
The present invention relates to an optical disk apparatus and method for tracking thereof. More particularly, the present invention relates to an optical disk apparatus and method for tracking thereof which can optimize the tracking of various sized optical disks by using varying tracking error signal sizes according to a capacity of the optical disk.
2. Description of the Related Art
An optical disk such as a Compact Disk (CD), and a Digital Video Disk (DVD) has a spiral track. An optical disk apparatus for reading the information recorded on the optical disk emits light onto the optical disk, and controls precise tracking for a pick-up part receiving light reflected from a recorded surface in order to detect data without errors. The tracking is controlled based on tracking error signals calculated according to high-frequency data read by the pick-up part.
FIG. 1 is a flow chart illustrating a conventional method for providing tracking for an optical disk apparatus.
Referring to FIG. 1, if an optical disk is inserted at step S10, a focus servo driving part is driven which controls the focusing of the pick-up part for reading data by placing a laser beam onto the optical disk at step S20. Then, a tracking error value is calculated without driving a tracking servo part for controlling the pick-up part to precisely track at step S30. The tracking servo driving part is adjusted to optimize tracking error signals based on the calculated tracking error signals at step S40, to compensate for the tilting of an optical disk during pick up. A sled servo driving part is driven which directly moves the tracking servo driving part and the pick-up part based on the calculated tracking errors at step S50. The sled servo driving part is not actually driven in the step of S50, but driven if comparatively there is a large change in track distance. If the pick-up part locates on the optical disk where data to be read is located via the above process, the gain of the tracking servo loop is adjusted at step S60, and the optical disk is reproduced at step S70.
The driving of the tracking servo driving part according to a conventional tracking error signal size is operated by firmware programmed based on a general optical disk having a storage capacity of 650 Mb. However, the capacity of optical recording apparatus has recently increased, and storage capacities of 700 Mb, 800 Mb and 870 Mb are now being provided. As such, if an optical disk having a capacity greater than 650 Mb is tracked by use of firmware programmed using a 650 Mb standard, the error distance varies based on the storage capacity of the media used. In general, the optical disk apparatus is driven a longer distance than it should because it's using a 650 Mb standard. In other words, the servo overshoots because the tracks are closer together than expected. Therefore, it takes the optical disk apparatus a longer time to track, which may result in the wrong operation being performed.